Field of the Invention
The field of the invention relates to paving methods and more specifically to a permeable paving system for easy and accurate installation of permeable paved surfaces in a variety of materials.
Background
Paved surfaces are seen everywhere, whether they be on grass, gravel, soil, rooftops, or hardtop. These surfaces usually include pavers of various materials, cobblestones, asphalt, concrete slabs in various forms, and specialty products made from exotic materials. Moreover, the paved surfaces are arranged in recognizable patterns and/or follow a defined path. In all respects, these provide the individual and general public with an aesthetically appealing, and functional surface where the populace may walk, ride, or drive in relative comfort, but in most cases these surfaces are impervious. The US Environmental Protection Agency is actively promoting “Green Infrastructure” as a way to reduce the amount of impervious surfaces. Permeable surfaces reduce the amount of storm water runoff that carries with it pollutants, and floatables that get into the waterways. Over seven hundred US cities have combined storm water and sanitary sewer systems. Large rain events overload sanitary sewage treatment plants causing sewage spills that pollute the waterways. One element of “Green Infrastructure” is “Permeable Paving”. This refers to a paving surface that allows storm water to pass through to a storage layer in the base where it can infiltrate into the soils below. If the soils do not percolate the water, or the desire is to retain the water, not infiltrate, the water can be conveyed out of the storage layer into an external drainage system, or used for rainwater harvesting. The paving surface can be porous asphalt, permeable concrete, permeable pavers, or any other surface material that allows water to pass through. Many of the impervious paved surfaces in municipalities are over infrastructure pipes and conduits that limit the depth of the storage layer. Paved surfaces, such as sidewalks, follow the terrain up and down changing the direction of slope of the paved surface accordingly.
While the end product or pavement may be functional and appealing, the process of installing the permeable paved surface is a time-consuming and inefficient task. Porous asphalt, permeable concrete, and the other types of permeable paving surfaces require most of the installation steps listed below, but the most time consuming permeable paving surface to install, and most costly, is pavers. For example, a typical permeable paver installation requires excavation to a desired depth, terracing sloped areas, removal of the excavated material, hauling and placement of the base aggregate material, installing an under drain or overflow pipe and connecting to an external drainage system, driving a plurality of stakes into the ground to set string lines to determine the proper elevation of the base aggregate, leveling the base aggregate, the compaction of the aggregate, driving a plurality of stakes to secure straight and flexible edging, the use of a pair of screed pipes on the surface of the compacted aggregate to establish the height of the bedding layer of aggregate, placing the bedding aggregate and leveling it by pulling a screed across the screed rails, setting a plurality of string lines to establish a guide for setting of the pavers in the desired pattern at the proper elevation using the string lines as guides, and installing stone chips in between the joints of the pavers. One solution to the above involves a structural module in U.S. Pat. No. 7,704,011B2 to Marshall, 2010, Apr. 27, which replaces the sub base aggregate. Due to the structural strength, and the increased water storage in a structural module versus stone, an installer gains the advantage of reducing the depth of excavation, and eliminating the sub base layer of aggregate. The structural module reduces the time and expense of excavation, purchasing sub base stone, hauling sub base stone, placing sub base stone, compacting sub base stone, and all types of permeable pavements can be used with it. The structural module does not address the problems of frequent measuring for setting stakes, or the driving of the stakes into the ground multiple times for placement of string lines, or the problem of a change in slope in the terrain of the area being paved, or the driving of spikes to secure straight or flexible edging. The structural module requires a plurality of surface paving layers, including a base layer of aggregate, be placed on top of it. This increases the overall thickness of the pavement structure which can be a problem when going over infrastructure piping, or where there is a high ground water table.
Another example involves an underlayment support layer of polymeric material in the form of panels that is porous as described in US Publication Number 2010/0284740 A1 to Sawyer. While this solution substantially reduces the time and expense of excavation, purchasing, hauling, placing, and compacting the base stone, the system does not provide for storage of water, or conveyance of water, or the problem of frequent measuring and driving stakes at the proper location for placement of string lines, or the driving of spikes to secure straight or flexible edging.
My previous U.S. Pat. No. 8,282,310B2, dated Oct. 9, 2012, discloses a paver installation system. However, that invention did not take into account the problem of slope in the terrain being paved, the problem of maintaining structural integrity of the grid after being cut by the installer, the problem of snow and ice accumulating on paved surfaces, the variety of permeable paving surface materials, or the problem of connecting under drain and/or overflow pipes to an external pipe system that may be connected to a drainage system or used for rain water harvesting.
Thus a permeable paving system solving the aforementioned problems is desired.